import Vue from 'vue'
import Router from 'vue-router'
import Login from '../components/Login.vue'
import Home from '../components/Home.vue'
import Welcome from '../components/Welcome.vue'
import Users from '../components/Users.vue'

Vue.use(Router)

const router = new Router({
  routes: [
    { path: '/', redirect: '/login' },
    { path: '/login', component: Login },
    {
      path: '/home',
      component: Home,
      redirect: '/welcome',
      children: [
        { path: '/welcome', component: Welcome },
        { path: '/users', component: Users }
      ]
    }
  ]
})

//  为路由对象，添加 beforeEach 导航守卫
//  挂载路由导航守卫
router.beforeEach((to, from, next) => {
  //  to 将要访问的路径
  //  from 代表从哪个路径跳转而来
  //  next 是一个函数,表示放行
  //  next()  放行             next('./login) 强制跳转
  //  如果用户访问的登录页，直接放行
  if (to.path === '/login') return next()
  //  从 sessionStorage 中获取到保存的 token 值
  const tokenStr = window.sessionStorage.getItem('token')
  //  没有 token 强制跳转到登录页面
  if (!tokenStr) return next('/login')
  next()
})

export default router
